Polyene aldehyde and alcohols



United States Patent POLYENE ALDEHY DE AND ALCOHOLS Hans Herlolf Inhotfen, Braunschweig, Germany, and Otto Isler, Basel, and Paul Zeller, Neuallschwil, Switzerland, assignors to Hottmann-La Roche Inc., Nutley, N. J a corporation of New Jersey No Drawing. Application December 23, 1953, Serial No. 400,124

Claims priority, application Switzerland December 31, 1952 5 Claims. (Cl. 260601) The present invention concerns polyene compounds and a process for the manufacture thereof, which process comprises treating a 2,7-dimethyl-octa-2,6-dien-4-yne-1,8- diol with an oxidation agent, condensing the 2,7-dimethylocta-2,6-dien-4-yne-1,8-dial (hereinafter called Cio-dialdehyde) with a metal organic compound and hydrolyzing the condensation product formed.

The process according to the invention may be represented as follows.

HOH!C =CH-CEOCH=GCHzOH Ha Ha I RX=metal organic compound (as defined hereinafter).

The starting material I, i. e 2,7-dimethyl-octa-2,6dien- 4-yne-1,8-di0l, may be prepared by aminotropic rearrangement of 2,7-dimethyl-octa l,7-dien-4-yne-3,6-diol (condensed from a-methyl-acroleine and acetylene dimagnesium dibromide) in aqueous acetone by means of sulfuric acid; yield about 60 percent. The product crystallizes in benzene and melts at 108.5109.5 C. Ultraviolet maxima at 272.5 m (e=23,500) and 288 m (e=l8,830).

The 7 oxidation of 2,7-dimethyl-octa-2,6-dien-4-yne-l,8- diol I is carried out by the action of high-valent metal oxides. The reaction is conducted in an organic solvent, such as acetone, ether, tetrahydrofuran or methylene chloride, at a temperature between 0 C. and the boiling point of the solvent used. Especially well suited as an oxidation agent is manganese dioxide, which is used at room temperature in dry acetone. If the oxidation is conducted in a large amount of acetone, in the presence of manganese dioxide in excess, the yield of Cm-dialdehyde 11 obtained is almost quantitative. The Cro-dialdehyde formed crystallizes in a mixture of petroleum ether and ether in yellowish needles melting at 68 C. Ultraviolet absorp tion maxima at 314 and 330 m The Clo-dialdehyde is condensed with 2 equivalents of a metal organic compound RX, R standing for an organic radical and X for the term Me Hal or Me (Me or Me represent dior monovalent metals), especially MgHal, ZnHal or sodium and lithium. The condensation products III thus obtained are hydrolyzed by the action of water, weak acids or of Patented Oct. 8, 1957 "ice The said Grignard compounds may be prepared in the usual manner. Thus, methylmagnesium iodide is formed for example by reacting methyl iodide and magnesium in diethylether. The acetylene Grignard compounds may be produced preferably by reacting ethyl magnesium bromide with the acetylene compounds in diethyl ether. For each one of the active hydrogen atoms of the acetylene compounds, one molecule of the ethyl magnesium bromide is necessitated. The condensation of the Grignard compounds formed with the Cin-dialdehyde is performed in the usual organic solvents, such as for example diethyl ether or tetrahydrofurane. The acetylene compounds may in turn be prepared as follows:

Methylbutenyne is formed by condensing acetylene with acetone and by splitting oil water from the condensation product.

1-hydroxy-3-methyl-pent-2-en-4-yne is formed by conclensation of acetylene with methylvinylketone and subsequent ally] rearrangement by treatment with acid. Upon reacting the product formed with dihydropyrane in the presence of acid, the tetrahydropyranylether of l-hydroxy- 3-methyl-pent-2-en-4-yne is produced.

3-hydroxy 3 methyl-5-(2',6',6'-trimethyl-cyclohex-1'- en-yl)-pent-1-yne is prepared by reacting dihydro-B-ionone with acetylene in liquid ammonia by means of lithium acetylide. When water is split off from the said product, 3-methyl-5-(2,6,6'-trimethylcyclohex-1'-en-yl)-pent-3-enl-yne is formed.

According to another mode of procedure of the present invention, the Cm-dialdehyde obtained by oxidation is condensed with 2 molecules of a lithium compound R-Li. R standing for the same radicals as above described for the Grignard condensation, preferably The preparation of the said lithium compounds is achieved in usual manner. For example methyllithium may be prepared from methyl iodide and lithium in diethyl ether. The lithium acetylide compounds are prefer ably prepared in liquid ammonia by reacting the acetylene compounds with lithium or lithium amide. For each one of the active hydrogen atoms of the acetylene compounds one molecule of lithium is required. The condensation of the lithium acetylene compounds formed with the Cm-dialdehyde is carried out preferably in liquid ammonia. The lithium condensation is the preferred manner of condensing the Cm-dialdehyde with acetylene and with 4-methylhex-3-en-5-yne-1,l-dicarboxylic acid diethylester. The latter is in turn prepared by reacting 1-bromo-3-methylpent-2-en-4-yne with sodium-malonic acid diethylester.

The condensation of the Cm-dialdehyde may be performed in an analogous manner also with the sodium compounds of the said acetylene compounds. It is preferred to operate in liquid ammonia. However, the sodium condensations lead to the formation of more side products and offer therefore no advantage over the lithium condensations.

According to an additional mode of procedure of the invention, the Cio-dialdehycle may be condensed with zinc compounds. The zinc condensations take in principle the same course as the Grignard reactions and the lithium condensations. The zinc condensations are particularly valuable in reacting the Cm-dialdehyde with u-bromoacetic acid ester and the vinylogs there-of, such as preferably the 'y-bromotiglic acid ester. The latter is formed by heating the corresponding tiglic acid ester with 1.1 equivalent of N-bromosuccinimide in carbontetrachloride while exposing to light.

When subjecting the condensation product of Clo-dialdehyde and 2 equivalents of -bromotiglic acid ester to a dehydration procedure, the 8,8-dehydro-crocetin-diester is formed, and by subsequent partial hydrogenation of the triple bond and by isomerisation of the hydrogenation products, the all-transcrocetin-diester may be obtained.

The products of the present invention are valuable intermediates for the synthesis of natural coloring agents, such as more particularly 1.9-carotene, bixin and crocetin.

EXAMPLE 1 Oxidation to Cio-diaidehyde parts by weight of 2,7-dirnethyl-2,6-octadien-4-yne- 1,8-diol are dissolved in 1500 parts by volume of dry acetone; 150 parts by weight of manganese dioxide (prepared according to J. Chem. Soc. [1952], page 1094) are added and the mixture is mechanically shaken for 2 hours. The manganese dioxide is sucked off, washed with acetone until the filtrate runs otf nearly colorless, whereupon the yellow acetone solution is concentrated in vacuo. Approx. 9.7 parts by weight of a solid, yellow residue, which is recrystallized from ether/petroleumether is obtained. The 2,7-dirnethyl-2,6-octadien-4-yne-1,8-dial has the melt- IVc is purified by recrystallization from benzene. Colorless crystals of melting point 9093 C. are obtained. Ultraviolet maxima in ethanol at 273 m (e=23,800) and 288 mu (e=20,000).

The condensation product [Va thus obtained Iva OH OH CH3% HC=CHCECCH=C-iJH-CH;

when oxidized with manganese dioxide yields 3,8-dimethyl-deca-3,7-dien-5-yne-2,9-dion of melting point 109-1 10 C. Ultraviolet maxima in ethanol at 234 m (=7,300) and 314 mu (e=27,300).

EXAMPLE 3 Condensation with methylbutenyne 7 parts by weight of methylbutenyne in 100 parts by volume of ether are added dropwise while cooling to an ether solution of ethylmagnesium bromide (prepared from 2.5 parts by weight of magnesium, 9 parts by volume of ethylbromide and 50 parts by volume of ether. The mixture is first stirred at room temperature for 30 minutes and then at 40 C. for 1 hour. The Grignard compound of the methylbutenyne is formed. After cooling down a solution of 4.8 parts by weight of Cm-dialdehyde in 15b parts by volume of ether is added, and the mixture is refluxed for 1 hour. Working up as usual yields 8.1 parts by weight of a viscous oil of n =1.5653. The Zerewitinotf determination gives values corresponding to 1.96 mol of active hydrogen. Ultraviolet maxima in ethanol at 223 my and 291 me.

The condensation product lVb thus obtained has the formula and may be converted into the crocetindialdehyde by partial hydrogenation of the triple bonds, allyl rearrangement of the secondary hydroxy groups and subsequent oxidation of the primary hydroxy groups formed.

EXAMPLE 4 Condensation with 1-hydr0xy-3-methyl-pent-2-en-4-yne An ethylmagnesium bromide solution is prepared from 6 parts by weight of magnesium, 21 parts by volume of ethyl bromide and 50 parts by volume of ether. A mixture of 12 parts by weight of 1-hydroxy3-methyl-pent-2- en-4-yne and 200 parts by volume of tetrahydrofuran is added dropwise thereto and the clear Grignard solution is heated at 50 C. for 1 hour. After cooling down, a solution of 4.8 parts by weight of Cw-dialdehyde in 200 parts by volume of tetrahydrofuran is added and the mixture is stirred overnight at room temperature. When worked up in usual manner, the tetrahydroxy compound IVc of the formula OH OH ing point 68 C. Ultraviolet maxima in ethanol at 314 m (e=29,000) and 330 mu (e=26,200).

EXAMPLE 2 Condensation with methylmagnesium iodide is obtained as a sirupy residue. Ultraviolet maxima in ethanol at 225 m 278 m and 292 my.

EXAMPLE 5 Condensation with the pyranylether of I-hydraxy-S- methyl-pent-2-en-4-yne To a solution of ethylmagnesium bromide (prepared from 3 parts by weight of magnesium, 10 parts by volume of ethyl bromide, 50 parts by volume of ether and parts by volume of tetrahydrofuran) is added a solution of 11 parts by weight of the pyranylether of 1-hydroxy-3- methyl-pent-2-en-4-yne (boiling pointo.1 G ll-61 C., n =l.4845) in 50 parts by volume of tetrahydrofuran 6 and the mixture is heated at 40-50" C. for 1 hour. After sulfate and concentrated in vacuo. The condensation having cooled down, a solution of 2.4 parts by weight product thus obtained has the Formula IV) of Cm-dialdehyde in 100 parts by volume of tetrahydro- 1v; H 0H furan is added dropwise and stirred overnight at room temperature. The reaction mixture is poured into a so- A lution of ammonium acetate in ice water and extracted with ether. The ether solution is washed with sodium EXAMPLE 8 hydrogen carbonate solution and water, dried with so- Condensation with 4-methyl-hex-3-e'n-5-ylie-1,1 -dicarb0xdium sulfate and concentrated. The condensation prodylic acid ethylester uct IVd of the formula A solution of lithium in liquid ammonia is prepared IVd CH2 CH:

is a viscous oil. Ultraviolet maxima in ethanol at 225 m, and 2.4 parts by weight of 4-methyl-hex-3-en-5-yne-1,1- 278 m and 292 m dicarboxylic acid ethylester (boiling pointiz 150 C.,

n =l.466) are added dropwise thereto. At the end, EXAMPLE 6 die blue color of the lithium disappears. Hereafter a COMdEm-HII'OH with y y- 1 3 solution of 0.84 part by weight of Cm-dialdehyde in ab- Y J' "y )-P -y" solute ether is added. After 1 hour, a small quantity of ammonium chloride is added and the solvent is evapo- 2.2 parts by weight of magnesium, 6.2 parts by volum rated. The residue is dissolved in ether, the solution is of ethyl bromide and 100 parts by volume of absolute washed neutral, dried and evaporated. The remaining h 10 parts b i h f 3 h d -3- h l-5- sirup is distributed between petroleum ether and 95 per- (2',6',6'-trimethyl-cyclohex-1'-enyl)-pent-1-yne (boiling cent methanol. The methanolic fraction contains the p0ll1ll0.02 76-78 C., n =l.492) in 100 parts by volume condensation product IVg sought for:

An ethylmagnesiurn bromide solution is prepared from IVa HnOaOOC OH OH COOCzHu HCOH:CH=C-CECCIEHC=OH EC-CH=CJIHCEOC=CH-CH2C HrGzOOO HI H3 H: H: OOOCzH of ether are added thereto. The mixture is refluxed for U. V. maxima in ethanol at 225 m 278 m and 1 hour. After having cooled down, a solution of 3.3 292 m parts by weight of Cio-dialdehyde in 300 parts by volume EXAMPLE 9 of ether is then added dropwise. The mixture is again refluxed for 3 hours. Working up as usual for Grignard Condensation with y'bmmoughc acid ester condensations yields 14 g. of a sirupy residue of 16.5 parts by weight of amalgamated zinc are covered n "=1.520. The Zerewitinoff determination gives values with 10 parts by volume of tetrahydrofuran. 3.9 parts corresponding to 3.96 moles of active hydrogen. Ultraby weight of Cm-dialdehyde are separately dissolved in violet maxima in ethanol at 277 my. and 292 m 25 parts by volume of tetrahydrofuran and 28 parts by The condensation product lVe thus obtained has the volume of -bromotiglic acid methylester (boiling pointn formula 90-92 C.) likewise in 20 parts by volume of tetrahy- IV: H5O CH: H8O CH:

OH OH 0H 0H CHz-CHr-(BCEC4IHC=CHCEOCH=CA7HCEOCH:-CH2

Hz HI H: H! CH: Rae

and possesses the carbon skeleton of fit-carotene. Condrofuran. To start the reaction, a small quantity of the version into B-carotene may be effected by partial hydro- -bromotiglic ester solution is added to the zinc and the genation of the triple bonds, two allyl rearrangements mixture is heated until the solution boils up and becomes and the splitting off of 4 moles of water. turbid. Then the Cio-dialdehyde solution and the 7- EXAMPLE 7 bromotiglic ester solution are added at such a rate, that the reaction mixture remains boiling actively. Once the Condensation with lithiumacetylide addition of the reactants is complete, boiling is continued for one further hour. After cooling down, 250 parts by welght cmdmlddfihyde are dlssolveg by volume of 10 percent acetic acid are added and the m 50 F by volume of tetrahy rofuran and adde mixture is extracted with benzene. The benzene extract dropwise to a solution of lithiumacetylide (from 0.5 part is evaporated The yellow Oil remaining back has ulmb y Weight of lithium) in liquid ammonia After pp violet maxima at 217 mu and 295 mu. By distillation 2 P by Weight of ammonium Chloride is under a pressure of 0.01 mm. and at an air bath temadded. Once the ammonia has evaporated, the mixture perature of 160 C., the major part of the side product,

is taken up in ether, washed neutral, dried with sodium which is formed by a Wurtz reaction of the -bromotiglic ester, can be removed. The residue of the distillation ester of melting point 213.5 C. (non-corrected) in the (11.7 parts by weight), which contains the condensation form of red, caterpillar-like crystal plates. Ultraviolet product IVh sought for of the formula maxima in petroleum ether 40-50 C.: 315 m (e=6650),

IVII OH OH CHsOCC=CHCH:( JHG=CHCEC-OH=CJH-CH:GH=CCOOCH;

Ha Ha Ha Ha may be converted by splitting off water into the 8,8'- 399 my. (e=81,000), 422 mu (e=135,300) and 448 m dehydrocrocetin-dimethylester and the latter in turn by 10 (e=139,000). subsequent partial hydrogenation and isomerisation into We claim: the trans-crocetindimethylester as follows: 1. 2,7-dimethyl-octa-2,6-dien-4-yne-1,S-dial.

The residue of the distillation is dissolved in 130 parts 2. A compound of the general formula by volume of benzene and, for the purpose of splitting OH OH off water, boiled for 10 minutes with 2 parts by weight of solid p-toluenesulfonic acid, using a downward con- R 05C H C=CH CEG CH=C JH OEC R denser. Thereafter, the p-toluenesulfonic acid is washed I HI ut from th r aC Solution y means of Sodium Y- wherein R represents a member selected from the group drogen carbonate solution. The solution is concentrated, consisting f h d d lower li h ti hydrocarbon filtered through an aluminumoxide column, rinsed with di l benzene, whereupon in order to remove low-boiling im- 3 A compound according to l i 2 wherein R purities the concentrated residue of the first filtrates is resents hydrggen,

subjected anew t0 a vacuo distillation. On cooling, 4 A compound according to claim 2 wherein R repthe distillation residue crystallizes. Recrystallization resents h di l from benzene/methanol yields 8,8'-dehydro-crocetin-di- C=OHI methylester of melting point 167-1675 C. showing the following ultraviolet maxima in petroleum ether 40-50 C.: 401.5 m (c=82,200) and 427 m (e=82,000). 5. A process of making a compound according to claim The hydrogenation of 8.8'-dehydro-crocetin-dimethyl- 2 which comprises condensing 2,7-dimethyl-octa-2,6-dienester in highly purified benzene with 1 mol of hydrogen 4-yne-1,8-dial with two mols of a metal-organic comin the presence of palladium catalyst, the activity of pound RCECX, wherein R represents a member sewhich is reduced by means of lead (Helvetica Chimica lected from the group consisting of hydrogen and lower Acta, volume 35, page 447), yields 8,8'-cis-crocetin-dialiphatic hydrocarbon radicals, and X represents a memmethylester of melting point 146 C. (non corrected), ber selected from the group consisting of HalMgand Li-,

light, water and iodide being thoroughly excluded durand hydrolyzing the condensation product obtained. ing the hydrogenation. Red needles from benzene/ methanol. Ultraviolet maxima in petroleum ether 40- R f r n s Cited in the file of this patent C.: 314 mu (e:39,700), 397.5 mg, (e=60,500), UNITED STATES PATENTS 420 m (e=90,5()0) and 446 m (e=81,000). The isomerisation of said compound to the transor "y-CIOCeIiII- 40 2609396 Inhofien et Sfipt' 1952 dimethylester may be effected, for example, in petroleum OTHER REFERENCES ether solution in the presence of iodine by exposure to Johnson: Chemistr f the Acct c light of a 5OO-Watt-Philips-Foto-bulb. For purification Pounds 1946 pages 290 i 0307' y om purposes, the product is suitably chromatographed on an Kanr: Organic Chemistry, 1946, page aluminumoxide column. Eluating the strongly adsorbing 4 orange colored zone yields the trans-crocetin-dimethyl- Heilbron et al.: J. Chem. Soc. 1943, 268-70. 

1. 2,7-DIMETHYL-OCTA-2,6-DIEN-4-YNE-1,8-DIAL
 2. A COMPOUND OF THE GENERAL FORMULA 